The Frustrations of Tough Guy Mike Wallace : Television: He acknowledges he was treated for depression during a libel trial brought by Gen. Westmoreland against CBS in 1985.

The door to Mike Wallace’s glass-walled office is closed for a few moments, but people keep coming in anyway. Producers half the age of the 72-year-old Wallace want to discuss long-term investigative pieces they’re doing with “60 Minutes’ ” bulldog inquisitor.

Wallace thrives on the bustle.

“Had it not been for ’60 Minutes,’ I’m sure they would’ve jettisoned me, thrown me over the side some place, because people want new faces, new reporters, new blood,” he says later. Instead, “60 Minutes” began its 23rd season Sept. 16 as the No. 1 show in the weekly Nielsens. And Wallace (who works for a 67-year-old executive producer in “60 Minutes” creator Don Hewitt) is not exactly ready for retirement.

“I have a contract until I’m 75, and then I’ll re-negotiate!” he says, laughing. “I’ll retire when my toes turn up--in other words, when I die. As long as I get the job done, what’s the point in leaving? Seriously, I’m a very bad solitary person; I need to rub up against people and ideas.”

A retrospective of that friction can be seen in a CBS News special, “Mike Wallace, Then and Now,” that airs at 10 tonight (Channels 2 and 8). The program--which marks Wallace’s 40 years in broadcasting--includes black-and-white kinescopes from his live 1950s talk show, some of “60 Minutes’ ” “ambush interviews” of miscreants, and profiles ranging from Golda Meir to Vladimir Horowitz and Malcolm X.

“It’s a stroll through 40 years of stories that I’ve done and people I’ve talked to,” says Wallace. “It’s a snapshot of this country, in a strange way.”

For a man who has made a career of probing the lives of his subjects, Wallace, like many journalists, has been remarkably private about his private life. But, during the interview, he said that he had been treated for depression in 1985 during what was probably the low point in his career, a $120-million libel suit against CBS by Gen. William Westmoreland.

(Westmoreland sued CBS and Wallace over a 1982 “CBS Reports” documentary for which Wallace was a correspondent. The documentary alleged that in the late 1960s, Westmoreland and other U.S. military officials in Vietnam conspired to mislead the President and the public about enemy strength in order to maintain popular support for the war. The general ultimately withdrew his suit in exchange for a statement about his patriotism by CBS. While CBS stood by the facts of the broadcast, the network’s own internal investigation acknowledged that the producer of the documentary had broken some of CBS News’ guidelines.)

In the middle of the trial, Wallace collapsed from exhaustion and was admitted to a New York hospital for several days.

“It triggered a clinical depression in me,” says Wallace. “I didn’t know that’s what it was. All I knew was that I was exhausted, emotionally exhausted. Only when the psychiatrist at the hospital came and saw me and talked to me and diagnosed it did I understand what it was. There were a lot of things going on. My marriage was busting up, I was moving out of the house that I’d lived in for 22 years, and I was on trial. When a reporter goes on trial for libel, you’re going to his gut. You’re going to his soul because you are calling him a cheat. If there’s anything that a reporter does not want to be called, it’s a cheat.”

He felt better as soon as the trial was over and persuaded his doctor to take him off the anti-depressant he’d been taking. Several months later, after returning from a trip on a story in Nicaragua, Wallace fell and broke his wrist playing tennis, triggering a second bout with depression.

“I was deeper in the second time than the first, and that went on for about six more months. I didn’t want to tell anybody here; nobody knew. They knew that I was acting very strangely, but they didn’t know what it was. That went on for some months. I knew what it was the second time around, and was back on that same thing and talking to the same guy.”

Today, Wallace says, “That’s now five years ago, and I feel wonderful. Part of the happiness, the energy that you understand in me is the self-knowledge that comes through having been through that kind of situation.”

Wallace has been married for four years to the former Mary Yates, the widow of producer Ted Yates, who encouraged Wallace to change the then-landscape of polite TV-talk as the creator of Wallace’s 1950s New York talk show, “Night Beat.”

This marriage, his third, seems to have softened some of Wallace’s edges. “I’m a very contented fellow,” Wallace says quietly. “Why not? I have a good job, I’ve got good health, and I have a companion to whom I’m utterly devoted.”